I got a chance to buy a set of used 5.3 heads cheap and was wondering how well they will flow with a full port/polish? Would it be worth it or just buy someother type of heads? I have a stock 4.8 that will be getting a cam very soon with a intercooled radix and shorty headers(about to be pacesetters.)

 

This is a very gray question. I properly ported set of heads will give gains with a larger cam with your applications. But gen3 engine heads flow very well and you won't get huge gains. Also, a forced induction engine won't see as big of gains from heads as a naturally aspirated engine. The air being forced in doesn't see as much restriction as air under vacume.

 

So basicly I should save my money for something else?

 

yeah, basically. Look at it this way as well. The 4.8 shares the same head with the 5.3. It flows well for the 5.3 thus it ought to flow extremely well for a 4.8 which generally has less demand for air. That can change with different pulley sizes but you get the point. You can gain from ported heads just not worth the $ at this point. If you plan on maxing out your combination then go for it. I can tell you for a fact that when i put a 3.25 pulley on my bone stock 4.8 and uped the boost to 11.5psi, that was my biggest and cheapest bang for the buck I got out of any mod I did. Night and day difference.

 

FWIW, I had a set of 5.3 heads that were milled .005 and had a pocket port job installed on my 4.8 recently along with a very mildl Lunati cam. My tune hasn't been updated yet, so I'm sure I'm not getting everything out of the motor.

I'd have to agree with MJHoward on this...you'll probably be happier if you spend a little more money for some aftermarket heads. Along with new springs and back-cut valves, I have about $700 invested in these heads and I still don't know if the gains were worth it.

 

i totally disagree. a good head job (no pun) will yeild nice results. even on stock heads. just make sure they get tuned afterwards. also, it helps to know people that can do some nice head work for good prices.

 

I would agree on a NA appl. but on FI engines the gain is usually not worth the $$$ or effort on a street vehicle.

 

why isn't the gain worth the money. i have a guy that will work a set of stock heads for a minimal price. 350 to 500 for a ported and polish job along with 3 angle valve job. he isn't in it to make money. everything is cnc'd.

the work is of high quality standards as well.

 

I wouldn't pull the heads and swap them even if the heads were free. If you have the engine apart already then that is a little different. On my 6.0, I couldn't put it together without doing a little port work myself.

 

In J.Whitten's case--since he already plans to do a cam and have it that far down--I think a smart spending of his money would be to install a set of 6.0L #317 heads, which are basically a larger 72cc combustion chambered LS6 design. These would flow better than the 4.8/5.3 heads, be economical (I bought mine new for $545--a used set with a clean up would be even cheaper), and most importantly allow him to run more boost (I'm running 10# on pump gas). The extra money would cover the cam cost or can go to a meth injection kit.